DE2727010A1 - METHOD OF OPERATING AN ELECTRO-OPTIC DISPLAY DEVICE - Google Patents

Description

Ρίβ7—

2 Dr. F. Zumstein Sr. - Dr. E. Ascmönn Cr. Γί. Koeni ^ sberger

Dipl.-Phys. R. Holzbauer - Dipl.-Ing. F. Kiingseiseii - Dr. F. Zumstein jun.

PATENT LAWYERS PA Or. Zumstein et el, BrautoeuaatraBe 4. BOOO Munich 2

S MUNICH 2.

BRÄUHAUSSTRASSE 4

TEUHFON: COLLECTION NO. 225341 TEUHGRAMME: ZUMPAT TFlFX 529979

3 / Li AG-712

Citzen Watch Company Ltd., Tokyo / Japan

Method for operating an electro-optical display device

The invention relates to a display device which makes use of liquid crystals, substances which are subject to electrical deformation due to an electric field of GlUhelementen, exothermic elements and substances used whose color changes depending on the temperature or similar parameters, and particularly relates to a Display device, the electrodes of which are connected in a matrix-like manner to display elements, the optical properties of which essentially depend on the effective value of the applied voltage.

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In a matrix control system, the display elements are grouped in η rows and q columns, the row control signals r being applied to the row electrodes and the column control signals C being applied to the column electrodes. In this case, a voltage with an effective value of V = UjT j (rC) dt is applied to the display elements at the crossing points between the row and column electrodes, T representing the duration or the cycle duration of the control signals. In accordance with the desired pattern to be displayed, control signals r and C are applied, the waveforms of which are applied to certain display elements with a high rms voltage, so that these elements are in the on-state, while other display elements are impressed with a low rms voltage so that these elements are themselves are in the switched-off state. If Von denotes the minimum voltage impressed on the switched-on elements and Voff denotes the maximum voltage impressed on the switched-off elements, then the ratio oc = Von / Voff can be called the working margin at this point in time. Although the absolute values of the voltages Von, Voff change as a function of the voltage of the energy source, the working margin is a constant which is determined by the control system and the working margin serves as a nominal value by means of which the quality of the control system can be assessed.

Because the changes in the optical properties of twist-sensitive nematic liquid crystals or nematic twisted liquid crystals are extremely little dependent change from voltage deviations, good contrast can only be obtained if the control system has an operating margin between about 1.7 and 2. A working margin, which is slightly above these values is particularly preferred for display devices of the reflective type when they should provide a good indication and against fluctuations in the voltage of the energy source over a wide temperature range should be resilient, as is then the case

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is when the. Display devices used in electronic clocks should be.

In a conventional control system, the line control signals have given waveforms which are unrelated to the display pattern and which are symmetrical with each other. Control signals which can indicate a combination of all 2 ⁿ patterns are applied to the row and column electrodes. The working margin is therefore small and is, for example, y = V (n + 3) / (n-1) for the 1/2 bias using two energy sources with three potential levels and. \ = I (n + 8 / n for 1 / 3 Biasing using four power sources with four potential levels, so it is extremely difficult to operate a row array over four or more rows.

In many cases there is to a certain extent a relationship between the display elements to be switched off and the display elements to be switched on for the display of numbers, letters, characters and for animation and it is then, if the display elements are switched in a suitable manner, not necessary to supply control signals corresponding to all 2 ^{n patterns.} On the other hand, among the 2 patterns, there are first certain patterns that are easy to control, that is, those patterns for which a large working margin can easily be obtained, and second patterns that are difficult to control, that is, those patterns that cause difficulty when an attempt is made to increase the working margin. A pattern of the second type is hereinafter referred to as the most difficult pattern. The working margin is actually determined by a certain combination of indicator oysts along several columns. Since the conventional control methods use control signals whose waveforms correspond to all of the patterns including the most difficult patterns of the above type, the working margin is limited to a low value.

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ORIGINAL

AT

borders.

The aim of the invention is therefore an arrangement of the display element connections, that will not create any of the most difficult patterns, or that will only create combinations of patterns that are easy to use using a control system that is appropriate for those patterns to be displayed control signals are applied to the row and column electrodes, which make it possible to achieve a large working margin or reduce the number of energy sources. A good looking display with good contrast can thus can be easily obtained and expediently used in display devices which are twist-dependent of reflective nematic liquid crystals or twisted crystals for clocks, electronic calculators and similar devices.

The invention provides a method for operating an electro-optical display device, the line and having column electrodes arranged in a matrix form to provide display elements at the crossing points between the To provide row and column electrodes so that the number χ of the display elements in a non-display State along a column electrode whose other display elements are brought into a display state, satisfies the following relationship

χ = s η - JL

where η is the total number of row electrodes and

1 are an integer greater than k but less than η, where k is expressed as

<η + n- l -Vn -n + 1
₌ __

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and where k is the largest integer satisfying the above relationship, which method is characterized in that two line control signals always have a voltage potential that satisfies the following relationship:

² dt = -4 R ²
n-1

where T = the cycle time,

ri = the voltage potential of the i-th row control signal,

rj = the voltage potential of the j-th line control signal,

t = the time and
R = a constant

denote, and that the column control signals have voltage potentials which satisfy the following relationship:

Cf ro- A ^ (rj- ro) j

where C β is the voltage potential of a column control signal denotes the η - 1 display elements in a non-display state and the other display elements brings it into the display state,

ro = the mean voltage potential of all row control signals ,

A β is a constant and

«= Denote the sum of the row electrodes, the display elements which are brought into an indicating state, where A is at least one of the fulfills the following relationships:

A = 2 / (n - I)

A = V < ⁿ - D / i Λ (η -1)}

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A particularly preferred idea of the invention consists in a method for operating an electro-optical display device, in which the row and column electrodes are arranged in a predetermined matrix shape, the most difficult Cough does not produce or only produces pattern combinations that are easy to control, which process is characterized by it is that two line control signals always have a voltage potential that satisfies the following relationship:

where T = a cycle duration,

ri = the voltage potential of the control signal of the i-th

Row,
rj = the voltage potential of the control signal of the jth row,

t = the time and
R = a constant

denote, and that the column control signals have voltage potentials which satisfy the following relationship:

C = ro - A 5 ^ 2 (rj - ro)

where C = the voltage potential of a splitter control signal is, the η - 1 display elements in the non-display state and the other display elements brings it into the display state,

ro = the mean voltage potential of all row control signals,
A = a constant and

, the sum of the row electrodes mean the on-pointing elements which are brought into the displaying state, where A is at least one of the following relationships:

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The following are preferred based on the accompanying drawing Embodiments of the invention explained in more detail:

Fig. 1 shows a graphical representation of the relationship between Von and Voff, which are parameters of the number of change the switched-on display elements and the switched-off display elements along a given column.

2a and 2b show an example of the electrode arrangement an electro-optical display device, in which the inventive method for operating the display device is used.

3a, 3b and 3c show the vector representations of the control signals which are displayed on the display device shown in FIG lie.

FIGS. 4a and 4b show the waveforms of the control signals which are plotted in the vector diagram in FIG.

Figures 5a and 5b show another example of the electrode arrangement an electro-optical display device, in which the inventive method for operating the display device is used.

FIG. 6 shows a vector representation of the control signals for use in the electrode arrangement shown in FIG.

FIG. 7 shows the waveforms of the control signals shown in FIG.

Fig. 8 shows in a graphical representation the critical value of the working margin, which is determined by the inventive Procedure is obtained.

9a, 9b and 9c show vector representations of control signals according to a further exemplary embodiment of the invention.

10 shows a vector representation of control signals according to another exemplary embodiment of the invention.

Fig. 11 shows in a diagram the waveforms of the in

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- si-

Fig. 10 shown control signals.

FIG. 12 shows the vector representation of the control signals according to a further exemplary embodiment of the invention.

Fig. 13 is a diagram showing the waveforms of the in Fig. 12 shown control signals.

Fig. 14 shows a vector representation of control signals according to a further embodiment of the invention.

15a and 15b show a further example of an electrode arrangement, in which the method according to the invention for operating the display device is used.

FIGS. 16a and 16b show a modification of that shown in FIG Electrode arrangement.

17 shows the vector representation of control signals according to a further exemplary embodiment of the invention.

Fig. 18 shows, in a diagram, the waveforms of the in Fig. 17 shown control signals.

19 shows the block diagram of a control circuit for an electro-optical display device according to the present invention Invention.

FIG. 20 shows in detail the electrical circuit of a part of the control circuit shown in FIG.

FIG. 21 is a diagram showing the waveform of the control signals obtained by the circuit shown in FIG v / earth.

FIG. 22 shows a modified embodiment of the row control circuit shown in FIG.

FIG. 23 shows a modified embodiment of the column control circuit shown in FIG.

24a and 24b show a modified embodiment of an electrode arrangement for an electro-optical display device, in which the method according to the invention is used for operating the display device.

Fig. 25 shows an example of an electronic calculator with an electro-optical display device, which according to the Process according to the invention can be operated.

26a and 26b show a further example of an elec-

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electrode arrangement according to the invention and Fig. 26c shows an example of the segment arrangement.

Fig. 27 is a symbolic representation of the electrode arrangement shown in Figs. 26a and 26b.

28 is a diagram showing the waveform of control signals, those used for the electrode arrangement shown in FIG.

Fig. 29 shows a manner of applying the signals to the column electrodes depending on whether they are in an indicating or a non-indicating state are to be brought in for the case in which the electrodes are in the form shown in Fig. 26 are divided manner shown.

Fig. 30 shows the numbers formed from seven segments from O to 9.

Fig. 31 shows the block diagram of an electronic watch with a liquid crystal display device according to the invention Process can be operated.

32 shows the block diagram of a decoder and a control circuit for the clock shown in FIG.

FIG. 33 shows in detail the circuit of FIG. 32 control circuit shown.

Fig. 34 shows in detail the circuit of a second decoder and the control circuit shown in FIG.

35 is a diagram showing the waveform for a modified one Example of the control signals shown in FIG.

Fig. 36 shows another modified form of the waveforms for the control signals shown in FIG.

37 is a diagram showing another example of control signals which are applied to a display device can, the four row electrodes and associated column electrodes, which are arranged in a matrix form to the invention Procedure to apply.

For the following description it is useful to use the vector representation to use for the waveforms of the control signals.

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A period or cycle time of the control signal waveform is divided into a plurality of intervals ti, t2 .... tj, and the control signal will have the same potential level over each respective interval. If T denotes the time for a period, / iL denotes the potential of the control signal over the i-th interval and ti denotes the duration of the i-th interval, then (Λ ti / 'f denotes the i-th component of the j-dimensional The η signal waveforms A1, A2 ... An are similarly divided into intervals and are represented as al, a2 .. .. expressed on when they are brought into the vector representation. the distance between the coordinates ak and al is equal to the effective value of the potential difference between the signal waveforms Ak and al. the signal waveforms A1, A2 .... an continue by another method the subdivision into intervals in vectors al ', a2 · .... are ^{transmitted to 1.} The coordinates al, a2 .... an and al ·, a2' ... an ¹ are congruent. In other words, it is possible to turn them around g to make a parallel movement and an inverse transformation congruent. The transformation of vectors into signal waveforms is carried out by a method which is the inverse method of the method described above. When the vectors al, a2 ..... an are transformed into signal waveforms, they can also be transformed into waveforms A1 ', A2 ¹ .... An ^{1 in} addition to being transformed into the waveform A1, Α2 ... An. The set of converted signal waveforms A1, A2 .... An obtained from the vectors al, a2 .... an, and the vectors al ·, a2 ^f .... an · resulting from their rotation, parallel displacement and inverse transformation are obtained, form a single group with exactly the same properties from the standpoint of the effective voltage applied to the display elements.

The following explains the meaning of the concept of the most difficult pattern. When the line control signals r1, r2 ... rn

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meet the following conditions, they are spoken of as control signals having symmetry. V / cnn r _Q is taken as the average of the control signal potentials for all the rows for each time, then with respect to a period T of the control signal i_ f ^T _{ri _ _r) ² at equal to the given value of R, independently of ^T ° of i, and

if (ri-r) (rj-r Mt is equal to the given value -R / (n-1), OV ο ο

independent of i and j if i and j

are unequal. When these conditions are expressed in terms of a vector, r1, r2 .... rn lie on a spherical surface with the center r, and when η is equal to or greater than 3, the points ri, rj, rk define an equilateral triangle whose side length 2nR / (n-1) is. C is referred to as a column control signal of a column, which turns off the display element of m rows out of a total of η rows and turns on the n-ra rows. The sum of the squares of the voltages on the display elements in the switched-off state, namely _s = - (V (ri-c) ² dt / T can be

Of f -> -T

are pressed as _{% £} ~] \ (π- ^, ² dt / _{T +} (η -,) / "V" -c) where the mean value T ^ JJ of the line-off signal is used. The sum of the squares of the voltages that are applied to the display elements when they are switched on, namely _s ==

is expressed as s

where the mean value F ^ of the line switch-off signal is used. If S _{oif is} kept constant, S can be brought to the maximum by taking C in the vector _{representation} lying on the extended line r _Qf , r Qn. When using a positive coefficient A, the expression is

V ^ ..., C = r _o - Ä 2_ (r} - r _Q. )

whereby . y ^{5 is} the sum of the

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switched lines reproduces, the cheapest. If this is the case, the voltages V _Qn and V _Qff which are applied to the display elements which are switched on and off when the line control signal has a symmetry are given by

From ² = {n-l + 2 (nm) A + m (n-in) A} -R ² / (nl) (1),

V _Qff ² = {nl-2mA + m (nm) A ² } .R ² / (nD (2),

From ² - Voff ² = 2nAR ² / (ii-l) (3).

The number k of turned-on display elements of the most difficult Pattern and the most appropriate value of A at that time are determined based on these equations.

ρ The procedure consists in proving that the value of Von

it is determined that the value of A corresponding to Von with respect to m from 1 to (n-1) is obtained, and that the voltage

Voff , which corresponds to each A value with respect to m from 1 to (n-1),

2 is obtained with the maximum value of Voff itself in the

m = O enclosing cases is given as Voff (max).

ρ p

According to this procedure, (Voof) max becomes a function of Von

2
where Von is determined to be the working margin

becomes maximum, and the number m which determines the value (Voff) max becomes equal to the number k of the switched-on display elements of the most difficult pattern. Although this can also be obtained by calculation , the general idea of FIG. 1 becomes clear.

Fig. 1 shows the relationship between the above-mentioned equations

2 2
with Von - Voff along the horizontal axis and

ρ
Voff are plotted along the vertical axis and m a

Parameter is. Line 2 and parabolas 3, 5 and 6 go

2 2

through the point O, R. The relationship of equals a constant is represented by line 1, which has a slope of

2
-1, the value of Voff from the third step of the above

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given method is represented by the intersection points between line 1 and line 2 as well as the parabolas 3, 4, 5 and 6, where (Voff ² ) max lies at point 7, which is the uppermost intersection point, the furthest on the left-hand side lies. If Von ^{2 is} changed, the point representing (Voff ² ) max moves along the curve 8, which is represented by a solid line. For a large working margin oL , a small value for Vof ^ / CVon ^ Vof is preferred. Therefore, when the point P is on the curve 8, it is best that the straight line connecting the origin point 0 · it the point P is brought into contact with the curve . This reflects the limit that can not be exceeded by the operating margin of a control signal system that can display a combination of all the patterns . F or η - 3 the inequality Λη +1 νίη ^ Γ is: _fc. n ² + nix £ ^ T is only fulfilled by an integer ' ²ⁿ - * " , and it can be seen that the straight line OP touches a parabola of a switched-on display element of the number ■ - K. In this case, the constants A and the working leeway t * given by: _{A =} yl _(n . _{1) / {Kln} . _K)}

and α A ⁿ

~ ^{X +}

-K) (n-1)

If η - 2, the point P is the intersection of a straight line f Ur ms 0 and a parabola ftlri-1, so that A «2 and OC - 3.

In a conventional matrix control method that makes it possible to combine all the patterns that provides applied in practice methods, such as the conventional 1/2 or 1/3 bias is not always necessarily a Spaltsteuer- eignal "it an ideal value for A because of Limitation of the voltages of the energy sources and the number of energy sources. Nevertheless, the work scope is by the state be excluded, are in the k display elements of a number of lines η • Inge Turns.

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For the most difficult pattern at η ^ 3 there is also for all combinations of columns that switch on display elements on a number of k lines out of a number of η lines, and columns that turn off the display elements on (n-k) rows. For η = 2 there are two types of columns at the same time, i.e. columns that turn one row on and one row off together with a column that turns off two rows.

The control method according to the invention is described below with reference to FIGS. 2 and 3. Figs. 2a and 2b show a Combination and an arrangement of the display elements of an electro-optical display device when used as Time display device. FIG. 2a shows the circuit of the row electrodes 21, 22, 23 and FIG. 2b shows the circuit of FIG Column electrodes 24 to 31. With these connections of the electrodes, a state will never occur in which a row display element is on while two other row indicators are off, regardless of which column electrode is looked at. This eliminates the most difficult display pattern and becomes all of them Avoided states in which the number m of switched-on display elements is equal to 1. When η = 3, it follows the same graph as shown in FIG. If this case, with the exception of the curve for m »1 is considered, the undesired pattern, which limits the working margin, will later be found at the intersections of m «O and m« 2. In this case the ideal value for A is 2 and the limit value for the working margin is equal to Y7 ". A display element 32 is located at the intersection of the Column electrode 25 und'der row electrode 21 and a display element, das.ein e segment reproduces is located at the intersection of the column electrode 25 and the row electrode 23, one of which is on and the other is off. However, there is no crossing point and thus there is no display element between the column electrode 25 and the row electrode 22, this never results

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State in which one line is switched on and two lines are switched off are. In other words, what was described as the most difficult pattern in the above does not occur. If, for example, one of the display elements 32 and 33 is switched on, a switch-on control signal can also be used with respect to of the row electrode 22, and a turn-off control signal of this electrode can be supplied when the Display elements 32 and 33 are both switched off at the same time. Although the column electrode 29 continues to have four display elements the element 34, which reproduces the a segment, and the element 35, which reproduces the d segment, be considered the same.

When the number of the display elements to be turned on is m = 2, there are cases in which one particular display element among the display elements to be turned off appears in three lines at the same time. It is therefore not expedient to give the line control signal an unbalance in order to achieve an improvement. If it is determined that the line control signal is symmetrical, the line control signals r1, r2, r3 form the vertices of an equilateral triangle which lie on a circle with the radius R in the vector representation. It is preferred that the column control signal Co, which turns off the display elements on all rows, is in the immediate vicinity of the center of the triangle. R is taken as the distance which separates the row control signal r3 from the column control signal C12 of the segments, which turns on the first and second rows and turns off the third row, and C12 is preferably chosen to be at a point furthest from r1, r2 away. Since the column control signal C123, which simultaneously switches on display elements on three lines, must be separated from r1 "r2, r3 by the distance of at least C12-r1, the limit value of the working margin can be increased to VT" for the ideal position shown in FIG. 3a In other words, r1 _f r2, r3 on a circle with radius R and the center

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Co and form an equilateral triangle that the three points C12, C13, C23 lie on a circle with the radius 2R around the center Co and form an equilateral triangle, and that the points (C13 _f r2, Co), (C23, Π, Co) and (C12, r3, Co) each lie on straight lines.

The following regularity, which will be explained in more detail later, can now be expressed. Namely, r1, r2, r3 are the vertices of an equilateral triangle with the center Co, and the column control signal Cab which turns on the display elements on rows a and b is located at a position obtained by drawing the straight line, the connects the mean value rk ^{of ra and} rb and the mean value Co of r1, r2, r3 with one another, is lengthened by twice the distance between these points. Although it is not shown in the drawing, C123 is still on a line perpendicular to the plane of the drawing and at a distance of V6R from Co. When the pattern shown in Fig. 3a is transferred into three-dimensional space as shown in Fig 3b, each of the points shown coincides exactly with the points on the grid, so that it can be seen that control can be effected using four energy sources and five potential levels.

If the x, y and z axes in Fig. 3b correspond to the intervals t1, t2 and t3 each correspond to half a cycle duration, the conversion of the vectors shown in the drawing into Control signal waveforms the signals shown in Figure 4a. If the drawing of Fig. 3a is further modified and is fitted to a grid shown in Fig. 3c is conversion to signals using two energy sources and three potential levels possible. The corresponding waveforms are shown in Fig. Ab. In this case it is the working scope / ff. This working margin is one Consequence of the fact that the value of Co differs somewhat from the mean

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value r differs from rl, r2, r3, and that Cab does not lie on the extension of the straight line connecting r _ab and r _Q. The waveforms are only shown for the important half cycle duration. The waveform for the later half cycle is reversed in level to remove a DC component.

Another example of the control method according to the invention is described below with reference to FIGS. 5 and 6. Fig. 5 shows a combination and arrangement of display elements when used for a numerical display device. FIG. 5a shows the connections for the row electrodes and FIG. 5b shows the connections for the column electrodes. From the fact that a decimal point is not displayed for numerical display of numbers from 0 to 9 and for zero suppression, it follows that a state in which a display element is turned on in one line and the display elements in the other three lines be switched off, does not occur in any column. If η = 4, the same graphic representation results as is shown in FIG. If this case is considered with the exception of the curve me 1, an undesirable pattern results which limits the .Working margin for the case ra = 2. The ideal value for A is 1, and it follows that in this case the working margin / 11/3 = 1 _f 932. When the relationships of the control signals are plotted in vector representation, the row control signals r1, r2, r3 and r4 assume the vertices of a regular tetrahedron and the rows of the control signals lie on a spherical surface, the center of which is the column control signal Co, which turns off all display elements on all rows . The column control signal C12, which turns on the first and second cells, is separated from r4 and r3. By a distance R and is arranged furthest from r1 and r2. For m = 3 and m = 4 the constraint is relatively free and there is considerable leeway. Hence, the points ^ ^C abc ¹ ^ ^{30 C} abcd ^are determined such that Von for m = 3 and m 4 equals Von for m 2. The ideal column control

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2Υ ~

signals for Co and m = 2 are indicated by in the vector representation the three-dimensional grid shown in FIG. 6 is determined. From this illustration the waveforms for four energy sources can be seen and five potential levels can be easily obtained. However, if a suitable transformation of the coordinates is carried out the number of energy sources can be further reduced. Fig. 7 shows an example of waveforms below Use of two energy sources and three potential levels.

Using a method described below, it is possible to obtain control signal waveforms for the general case. The combination and arrangement of the display elements is assumed such that no column occurs for m1, m2 ... m3, which reproduce the number of several switched-on display elements for the trick display or the like. With V ² On - V ² off along the horizontal axis and V ² off along the vertical axis and omitting m1, m2, m3 ... a graph is drawn showing the relationship of equations (2) and (3 ) with respect to m, and a curve is drawn connected to the uppermost curve. When a line is drawn from the point of origin so that it touches the curve, the point of contact provides the number of switched-on display elements of the undesired pattern, depending on which curve it lies on. The coordinates of the point of contact enable column control signals to be obtained which control the columns of the undesired pattern.

Not only is the most difficult possible pattern excluded, but the control signal system in which the number of display elements to be switched on is limited to a small number, significantly improves the working latitude and has a far-reaching influence on the fact that it is possible to display graphical representations, symbols and animated drawings. It is the same even with a matrix display device

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get a sufficient contrast in which. the number of Lines exceeds ten lines.

A third preferred example of the control method according to the present invention will now be described, in which 1 is greater than k and in which it is assumed that 1 is an integer smaller than η. In this case, there is no column showing a pattern in which the number of display elements to be turned on in a single column is between 1 and 1-1. In other words, since m is greater than 0 and 1, the undesired pattern is determined by the intersection of m = 0 and m = The ideal value of A, which can easily be calculated, is 2 / (n-1). The limit value of the working margin is thus ^α - \ / i + 4n / {(ni) (n- £)}. The following control signal occurs. At . In the vector representation, symmetrical row control signals with the column control signal Co of that column as the center point that switches off all rows, the column control signal Cl of those columns that switch on 1 row and switch off (n - 1) rows is on a line that has the mean value r of all row control signals and connects the mean value r ~ p of the line control signals of the display element lines to be turned off. Cl and r ~~ TT, r are aligned at points where the distance between Cl and r _Q is twice the distance between r and r _f ~. Although these are the ideal ratios, slight deviations have almost no effect when it comes to changing the working range. There are several ways in which column control signals other than Cl can be determined: (a) The value for A is taken such that the value of Von becomes equal to that of Cl. In this case, Voff is less than Voff of Cl.

(b) A value is assumed such that the value of Voff becomes equal to that of Cl. In this case, Von becomes larger than Von of Cl and occurrence of non-uniform shading of the liquid crystal is an undesirable condition.

(c) Assume a value for A equal to that of Cl, and

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Areas where Von and Voff are insufficient are shown with Provided intervals over which the line control signal has the same potential level. The column control signal shows over these intervals a change in the potential level and take at

ο? ο ρ constant difference from V on - V off from and V off to.

In order to express this in the vector representation, a different column control signal than C1 is provided in a dimension which is separated from the space containing the line control signal and Cl. This corresponds to the first embodiment for η = 3 » 1 = 2 and the second embodiment for η = 4, 1 = 2.

The following is a fourth preferred example of the present invention Method described in which no pattern occurs, which turns off all lines of the above pattern. For η - 1 = 2, the limit value of the working margin is further increased. Although for η - 1 = 3 and η> 9 theoretically there is a difference to the case described above, this difference is essentially equal to 0. The undesired pattern is that pattern which turns on 1 display element and η - 1 display element turns off, and the ideal value for A is

l / (n -]) / {i. (n-i.)} * where the limit value of the working range

\ n-i + \ ii {ni.) (nl) is. With η - 1 = 1 and A = 1 the yi, + Ji, (n- £ nn-i) working range is infinitely large.

Fig. 8 shows how the working margin of the present display device can be improved. The theoretical limits of the working range are plotted along the vertical axis, while the number η of the matrix rows is plotted along the horizontal axis. With 81,82,83 control signals are designated, which can control all pattern combinations including the most difficult patterns, 81 a 1/2 bias, 82 a 1/3 bias and 83 represent the theoretical limit value for a case in which the

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No limitation is imposed on control signal waveforms. 83 to 87 are for the embodiments 1 to 4 of the invention Related to the procedure and 84,85,87 denote control signals, which do not display a pattern in which the number of switched-on display elements is between 1 and 1-1, and at 84 for the case 1 = η - 3, at 85 for the case 1 = η and at 87 for the case 1 = η - 1. 86 denotes a control signal, that does not display a pattern in which the number of. switched on display elements is between 1 and 1-1 for 1 - η - 2.

So far, embodiments of the invention have been described on the assumption that the control signals have a symmetry to have. Of course, unbalanced control signals can also be used.

A fifth preferred exemplary embodiment is described below with reference to FIG of the control method according to the invention described. The most difficult pattern that in the display elements occurs on two rows and q * columns, then if at the same time columns appear which display patterns of three types, namely of the type in which the display elements are on of the first and second rows are both turned off, of the type in which the indicator on the first row is turned on and the indicator on the second row is turned off and of the type that the indicator on the second Row is switched on and the indicator on the first row is switched off. According to a special combination of the display elements, an attempt is now made to make the appearance of the third pattern impossible. The line control signals r1 and r2 and the column control signals Co, C1, C12 are ideal Case represented by the vectors shown in Fig. 9a, rl, Co, r2 and C1 lie in this order on a straight line Line equidistant from each other, and r1C1 is equal to r1C12 and r2c12. These control signals are in a grid in

. 709852/0958

Fig. 9b plotted. In this case, the control is carried out with three energy sources and four potential levels and the working margin is 3 · Thus, one energy source is less sufficient than was the case with a control signal that can display all patterns. Two potential levels of 0 and 2R for the column control signal are still sufficient. If the transfer is made to the points of the grid in Fig. 9c, the control can be achieved with two energy sources and three potential levels and the working margin is given a value of 76. This value is greater than the value of 75 for a control signal that includes all patterns and that has the same number of energy sources. This is attributable to the fact that in the known method, the size of C1r1 could not be increased because the angle defined by rl Co r2 was a right angle and the angle defined by r1 r2 CI was 135 °. According to the invention, the angles defined by r1Cor2 and r1r2C1 in FIG. 9b are 180 ° and the angles defined by r1Co r2 and r1r2C1 in FIG. 9c are 120 °, so that the working margin can be increased. In FIG. 9c, the coordinates of C12 do not lie in the present dimensional space, but these coordinates are represented by the point 91 which is projected into the drawing. The point can be anywhere provided it is equidistant from r1, r2. Description of the control signal waveforms is omitted because these waveforms can be easily obtained from the illustration in Figs. 9b and 9c.

Although description has been given of the case where r1 is the row to be turned on , when r1 and r2 are the rows to be turned on alternately, it is permissible to exchange the row control signals each time, which is achieved by a simple decoder modification. It is also allowed to shift the overall control signal level.

In the following, with reference to FIGS. 10 and 11, a sixth preferred

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described embodiment of the control method according to the invention. The most difficult pattern appearing on the display device with 3 rows and q columns occurs in the case where the display elements are turned on on all three lines at the same time in the form of a pattern in which one display element is to be turned on in one row and the display elements are to be turned on in two rows must be switched off. Even if this pattern is present, the working margin can be improved by using non-symmetrical line control signals, provided that the pattern to be turned on has been decided. In the present embodiment, the case is described in which no undesired pattern occurs which would lead to the switching on of display elements on a third line, one display element being switched on on one line and the display elements being switched off on two lines. Fig. 10 shows a favorable relationship between the line control signals R1, R2 _f r3 and- the column control signals Co, C1, C2, C12, C13 and C123. The line control signals lie on a circle with the radius R around a center point Co, but have no symmetry and the distance r1r2 between lines with display elements to be switched on is greater than r2r3 and r1r3 between a line with display elements to be switched on and a line with display elements not to be switched on. In this case r1r2 V ~ 2 χ rTr3. C2 r1, C2 r3, C1 r3, C1 r3 and C12 r.3 are smaller than r and the minimum / values represented by C1 r1, C2 r2, C12 r1 and C12 r2 are made as large as possible. Each coordinate corresponds exactly to the respective point on a rectangular or conical grid. C123 is separated from Co by the distance 2R on a line that is perpendicular to the plane of the drawing.

The control signal waveforms obtained in FIG. 10 are shown in FIG Fig. 11 shown. The index of the letter C denotes the number of lines whose display elements are to be switched on,

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and O means that there is absolutely no line whose display elements are to be switched on.

A seventh preferred example of the control method according to the invention is described below with reference to FIGS. In this example, the unwanted pattern does not appear on the second and third lines. In other words, the following describes the case in which, apart from the first line, there are no lines whose display elements are to be switched on in an undesired pattern. This means that the line control signals lie on a circle with the radius R around the center point Co, but have no symmetry, and that r1r2 and r1r3 between the lines to be switched on and the lines which are not to be switched on in an undesired pattern have a value greater than r2r3 between the lines that are not to be switched on. The distances C1r2, C1r3, C12r3, C13r2, which are all smaller than R, are chosen so that the minimum values of C1r1, C12r1, C12r2F, C13r1 and C13r3 are as large as possible. Therefore r1r2, r1r3 1 + YÜnal are as large as r2 r3. C123 is at a point separated from Co by Υ2 + 2 · ^ 2 on a line that is perpendicular to the plane of the drawing. Fig. 13 is a graph showing the control signal waveforms based on the graph of Fig. 12. When the direction of the Z-axis is converted to the third interval, t3 is increased and an excessive increase in the voltage of the power source is avoided . In this case, the limit of the working margin is % + 2 ~ ί2.

In FIG. 12, the four points r3 Co r2 Cl form a square with the side length R and lie C12 C13 Π on the diagonals of the square and at a distance R from its vertices. However, the potential levels given in Fig. 13 are rather complicated, and expressed with V1 in terms of units, V2 is given as (1+ V2) V1, V3 is given as T5 + 4 \ T? V1 and VA is given as 7 ^ + v7? V1-V2.

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An eighth preferred example of the method according to the invention is described below with reference to FIG. In this embodiment, a display device with 4 rows and q columns is used and the case is described in which the undesirable pattern in which a display element is to be turned on in one row and the display elements in three rows are to be turned off does not occur in more than one row. The line control signals lie on a circle with the radius R around a center point Co, but have no symmetry and r1r2, r1r3 and r1r4 between the lines to be switched on and not to be switched on in the undesired pattern are larger than r2r3, r3r4 and r4r2 between similar lines that are not to be switched on. C1r2, C2r3, C "Tr4 \ C34r2, C34r1, C23r1, C23r4, C24r1 and C24r3 are smaller than R and are selected so that the smallest values of C1r2, CTr3, ÜTr4", C23r2, C23r3, C24r2, C24r4, C34r3 and C34r4 are as big as possible. Therefore r1r2 is 1J7 / o χ r 5 · r2r3r4 form an equilateral triangle with side length 2T30 'R / 7 and Co is at a distance of 3R / 7 from the center of the triangle. In this case the working margin is 13/7.

In the following, 17 and 18, a ninth preferred embodiment of the method according to the invention will be described with reference to FIGS. 15,16. 156, 15b and 16a, 16b show arrangements of display element combinations for a numerical display device, with FIGS. 15b and 16b showing the row electrode connections and FIGS . 15a and 16a showing the connections for the column electrodes 155, 156. With 155 is a first row electrode 152 with a second row electrode, designated by 153, a third electrode line 154 and a fourth row electrode. If either Fig. 15a and b or Fig. 16a and b are combined, occurs regardless of which column electrodes 155, 156 be will seek, no Z stood up _and in which a display element is turned on in a line and the display elements in the other three lines are switched off because decimal points for

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a numeric display from 0 to 9 and for zero suppression cannot be displayed. An undesirable pattern, i.e., a pattern in which display elements turn on in two lines and display elements are switched off in two lines, thus does not occur in all lines. Unwanted patterns except those where the first and second lines, the first and third lines, and the second and third lines are turned on will not occur. The scope of work at The second embodiment can thus be greatly enlarged by using a non-symmetrical line control signal.

17 shows the ideal relative position between the row control signals r1, r2, r3, r4 and the column control signals CO, C12, C13 and C23. The line control signals r1, r2, r3, r4 lie on a spherical surface with the radius R around the center Co, and r1, r2, r3 are plotted at such points that they form an equilateral triangle. The control signal for line r4, which is not to be switched on, is located on a line which passes through the center point of the equilateral triangle, so that the distance r1r4 is less than the length of the side of the triangle. C12r3, C12r4, C13r2, C13r4, C23r1. C23r4 are smaller than R, and if these values are chosen so that the smallest values of C12r1, C12r2, C13r1, C13r3, C23r2 and C23r3 become as large as possible, then each of the squares Co r3 C12 r4, Co r1 C23 r4 and Co r2 r4 C13 is a square with sides of length R. r1r2 therefore T ^ / ^ times the size of r4ri, and the working margin is equal to the second

Fig. 18 shows an example of the obtained control signal waveforms. The x, y and z coordinates of Fig. 17 correspond to the intervals ti, t2 and t3, and these intervals are set to a ratio of 3: 1: 4, respectively, and t4 is made equal to t3 / 4 , so that the ratios are integers between the potential levels.

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19 shows the structure of a preferred one in a block diagram Example of an electro-optical display device in accordance with the present invention. With 201 is a Denoted display panel, and 202 and 203 denote electrical conductors to the row and column electrodes for transmission of control signals. These conductors consist of a first group 202a, 202b ... 202n and a second group 203a, 203b ... 203m. With 204 a display area is designated,

the display elements 204-1-1, 204-1-2, 204-2-1 ....

204-n-m is built. The individual display elements exist made of an electro-optical material which is made between a conductor from the first conductor group 202 and between a conductor the second group of conductors 203 is switched. As an electro-optical Material can be liquid crystals, an electro-chromic material, materials such as PLZT, i.e. polycrystalline lead zirconate titanate with added lanthanum, which is subject to a change in the crystal structure due to an electric field, Semiconductors, such as light emitting diodes, materials that are subject to elastic deformation due to an electrical Field are subject to discharge elements, glow resistors, exothermic elements and materials that vary in color depending on of temperature changes show electrophoretic materials, coils and magnetic elements and electrochemical materials that show a color change can be used. With 205 a line control circuit is referred to, which generates line control signals, which are applied to the first group of conductors 202, with substantially independent signals on the respective conductors 202a, 202b ... 202n. Essentially independent * is to be understood as the integral of

xi (t) -EoHxj (t) -Eo} dt i _m compared to o. . -. ι

tO + T '

f-tO + T 2 _r tO + T 2

·. \ {xi (t) -Eo} dt, J {xj (t) -Eo} dt for an arbitrary one / to to

Voltage level Eo, an arbitrary time to and a time interval χ is sufficiently small over which the electro-optical

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Material illuminates when the voltage waveforms for the ami-th and amj-th conductors pass through Xi (t) and Xj (t) are given.

With 256 a column control circuit is designated, the column control signals generated, which are on the second group of conductors, with control signals to the respective conductor 2Ö3a, 203b .... 203m can be applied to the information obtained from the display information signal 1 generator 207. the Column control signals have the same waveforms as the row control signals applied to conductors 202a, 202b .... 202n and are in phase with these signals, or the column control signals are substantially independent in phase of the signals on these conductors. With 208 a clock pulse generator for operating the display device is referred to, which can also serve as a clock for the display information signal generator 207 if necessary. In the Finally, the drawing does not show the energy source for the display device.

As far as the mode of operation of the display device is concerned, the display elements 204-1-1, 204-1-2 ...

204-1-n considered between the conductors 202a, 202b

202n and conductor 203a. The one impressed on the display elements Voltage is equal to the voltage difference between the control signals supplied to the two conductors, which are associated with each respective display element. Thus, if the control signal, which is on conductor 203, and the control signal, that is applied to conductor 202 are in phase, a voltage becomes equal to the difference between those of the conductors 203a and 202a supplied control signals is applied to the display element 204-? 1-1, which is connected thereto. If both Control signals have the same voltage, the display element will be in the unselected state because the current Voltage equals 0. The display elements 204-1-2 ... 204-1-n are all in the selected state because they have

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be supplied with a voltage that is not equal to 0, which is the It can be attributed to the fact that the control signals carried by conductors 2O2b .... 202n and 2O3a are independent of one another are. Assuming that a control signal supplied through conductor 203a is different from each of the control signals which supplied by conductors 202a ... 202n is independent, the entire column of display elements is 204-1-1, 204-1-2 .... 204-1-n, which are connected to the conductor 203a, in the selected state, since each of these display elements has one Voltage that is not equal to O is impressed. Thus, a single arbitrary display element in the display element column 204-1-1 ... 204-1-n can be brought into a non-selected state or all display elements in this column can be brought into a selected state, in which either it is ensured that a control signal that is sent to the conductor 203a is in phase with any of the control signals provided to conductors 202a .... 202n, or that the control signal supplied by conductor 203a is from each of the control signals supplied to conductors 202a ... 202n belong, is independent. In the same way, the signals provided by conductors 203b ... 203m enable a single one bring arbitrary display element in a corresponding column to an unselected state or all Display elements in a corresponding column in the selected Bring state. Therefore, the display device can operate to display the graph of a monovalent Represents puncture. It is also possible to reduce the energy consumption and the service life of the display elements by periodically applying the control signals, and then either with the conductors during the rest period connected circuit is short-circuited or opened. The control signals can also be time-multiplied and used for this purpose to bring a plurality of display elements into an unselected state one after the other.

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Fig. 20 shows a specific embodiment of the row control circuit 205 and column control circuit 206, and FIG. 21 shows the associated voltage waveforms. With 210, 211, 212, 213 and 214 T-flip-flop SDA circuits are designated, which are connected in cascade, and 215 denotes the input terminal for their initial stage. The outputs A1, A2, A4, A8 of the flip-flop circuits are connected to the input terminals a group of exclusive OR gates 202 of the row control circuit 205, and at the input terminals of an AND gate group 221 of the column control circuit 206. The outputs A1 to A8 of the flip-flop circuits and the outputs of the exclusive OR gates 220 are on the input side of a blocking contact group 222, which is triggered by pulses from the clock pulse input terminal 223 can be obtained. The output side of the blocking contact group 222 is connected to the respective conductors 202a, 202b... 202n of the conductor group 202. The blocking circuit 222 is used also as a power amplifier for operating the display elements. At 224 is a signal source for storing the display information signal designated. When an input signal is on one of the information selection lines 225, pulses appear as information output signals on the signal output line 226. The signal output line 226 is connected to the input terminals the AND gate group 221 and together with the output of the flip-flop circuit 214, with the input terminals of a NOR gate 228 in connection. The output terminals of the AND element group 221 are combined via an exclusive OR group 229 with the output of the NOR gate 228 at the input terminals of an OR gate 230. The output of the OR gate 230 is with the Input terminals of blocking contacts 231a, 231b ... 231m connected, which are connected via the respective information selection lines 225a, 225b .... 225m, which form the information selection line 225, are triggered. The output signals from the interlock circuits are obtained, are on the input side of a group of blocking contacts 232, which are triggered by pulses that are applied the clock pulse input terminal 233 appear. The starting page

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the blocking contact group 232 is connected to the respective conductors 203a, 203t) .... 203m connected.

During operation, signals with those shown in FIG. 21 are grounded with b, c, d, e and f denote waveforms at the respective outputs A1, A2, A4, A6 and A16 of the flip-flop circuits Ms 214 obtained when clock pulses denoted by a in FIG are at the input terminal 215 of the flip-flop circuit 210. A waveform circuit that is the exclusive OR gate group 220, supplies to the i-th input terminal of the blocking contact group 222 on the basis of the signals at the outputs A1, A2, A4 and A3, if i is a binary number

2 4 and assuming i = a. ^ + A ^ x2 + a, x2 + ^a Q x 2 ', the following waveform Xi:

Xi = U ₁ -A ₁ ) © ^(a 2 ' ^A 2 ^} ® ^(a 4 * ^A 4 ⁾ ® ^(a 8 " ^A 8 ^{) f}

where © denotes an exclusive OR link and £.) denotes an AND link. For example, there is an input signal waveform at the fifteenth input terminal as indicated by g in FIG. The pulses labeled h, which have the same period as the pulses applied to the input terminal 215 of the flip-flop circuit, but are phase delayed, are applied to the clock pulse input terminal 223 of the lock 222. At the output side of the barrier 222, namely on the conductors 202a, 202b. The waveform that appears as an output signal on conductor 202a, is denoted with 21 i in Fig.. If the period of waveform A8 is denoted by X and Eo is taken as the average of the high and low levels of the control signal,

_r to + T then j ^ _{i (t} ) -Eo} {xj (t) -Eo} dt = o, i / j.

Therefore, the control signals, which appear as output signals to the conductors 202a, 202b .... 202n, independently of one another.

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The following describes the formation of a control signal which is emitted through conductor 2O3. When an input pulse occurs on one of the information selection lines 225 is, the signal source 224 emits an information signal in the form of a binary number and as an output signal transmitted on the signal output line 226, which indicates the location of a corresponding row which is in an unselected State is to be brought. A signal b1 of the integer 1 is output on the line 226-1, a signal b2 of the integer 2 is provided on line 226-2, a signal b4 of integer 2 is provided on line 226-4 and a Signal b8 of the integer 2 is on line 226-8. These signals are sent to the AND gate group 221 and the exclusive OR gate group 229, which perform the following operations: Y = Lx A, Qb ^ χ k ^) b. χ A. + bo x Aq. This is therefore the same as the Xj signal that goes through

2 ^
j = b ₁ + b ₂ * 2 + b ^ * 2 + b _Q * ?. is pictured. If j ^ 0, the output signal of the exclusive-OR gate goes in the form as it is, through the OR gate 230 and the output signal is applied to the input terminals of the locks 231a, 231b .... 231m, whereby the locks for the rows selected by the information selection line 225 are set. If j = 0 and there is no position to be brought into an unselected state, the signals carried through the signal output line 226 at this point in time are all zero, so that A ../- at the output of the NAND gate 228 appears, goes through the OR gate 230 and is connected to the input terminals of the locks 231a, 231b .... 231m. During the short time interval that begins after a pulse is applied to the input terminal 215 of the flip-flop circuit and lasts until a pulse is applied to the clock input terminal 223 of the lock 222, the entire information selection line 225 is scanned and the signal levels in saved in all locks 231a, 231b ... 231m. If pulses are applied to the clock input terminal 233 of the lock 232, the time-

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lent coincide with the pulses to the clock input terminals 223 of the lock 222 are, are obtained from the locks 231a, 231b 231m output signals ter to the Lei 203a, ... 203m 2O3b synchronously be issued with the signals applied to the group of leaders 202 can be submitted. In accordance with the content of the signal source 224, a signal having a waveform identical to the j-th signal Xj of the conductor group 202 for j f 0 and a signal having a waveform identical to that of A ,. r for j = 0, is delivered to conductor group 203 synchronously with the pulses at clock input terminals 223 »233. If j = 0 and if the period of the waveform A ^ g is given by T, and the mean value of the high and low voltage levels of the control signal is denoted by Eo, then · C ^ {xi (t) -Eo} {X - Eo} dt = ο A ₁ g is therefore independent ναι of each waveform Xi. to ¹⁶ The OR element 228 and the OR element 230 are provided in such a way that there is no DC voltage component at the display element 204 when j = 0 . However, in those cases where the presence of a DC component is acceptable, such as those where incandescent elements are used, the final output signal obtained from the exclusive OR group 229 can be fed directly to the inputs of the locks 231a , 231b ... 231m.

22 shows a modified embodiment of the line control circuit 205. A random number generator 251 is designated which is constructed in such a way that it generates η random numbers in synchronism with the signals which are supplied by the clock pulse generator 208. The random number generator makes use of random physical phenomena, such as thermal noise or atomic nucleus decay, or uses a device which generates pseudo-random numbers and is constructed from digital computing circuits. In particular, it is possible to use the functions of a computer in combination when the display device according to the invention is used as a computer display. The η output signals from the random number.

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generator 251 are connected to the η input terminals of the blocking contact group 222, and random signals are stored synchronously with the presence of signals at the clock input terminal 253, the random number signals being supplied as control signals to the respective conductors 202 of the display device 201. In the case in which a DC voltage component is undesirable in the control signal, as is the case when a liquid crystal display element is operated, a single clock cycle is further divided into a first and a second half. During the first half of the cycle the random number signals as they are used are used as control signals, while during the second half of the cycle signals are used as control signals which are the reverse signals of those signals which were used during the first half. Furthermore, it is not absolutely necessary for the random number generator 251 to generate η output signals at the same time. A small number of random number signals can be generated in sequence and then distributed across all of the locks 222 in turn. When use is made of random numbers for the control signals, there is no periodic regularity, so that even if the period of the clock pulses is quite small, there is no regular display noise, which is particularly useful when the number of conductors 202 is large.

23 shows a modified embodiment of the column control circuit 206. This embodiment of the column control circuit 206 generates column control signals which are based on the control signals which are generated in the row control circuit 205. The data input terminals 262a, 262b .... 262n of a multiplexer 261 are connected to a signal source in the row control circuit 205, ie at the respective output terminals of the exclusive-OR group 220 in FIG. 20, so that the conductors 202a, 202b ... 202n signal level to be delivered is received by the multiplexer as input signals

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7727010

the. The input information to be displayed is due to the Address input terminal 263 of multiplexer 261, and address input signals, which correspond to these inputs are selected from the inputs 262a, 262b ... 262n and the output terminal 264 supplied. At this point it should be noted that the multiplexer can be constructed so that it Transfer members 265a, 265b .... 265n contains. The output terminal 264 of the multiplexer is connected to blocking contact groups 231a, 231b ... 231n and a blocking contact group 232. The output signals of the multiplexer due to the scanning of the Signals passed through the information selection line 225 are sequentially applied to the locks 231a, 231b .... 231η and supplied as control signals to the respective conductors 203 in synchronism with the application of signals to the clock pulse input terminal 233. If the number of terminals at the output 202 of the line control circuit 205 is small, can without difficulty Multiplexers installed in a number equal to the number m of terminals for the output 203 of the column control circuit 206 will. In this case, the control circuits 205 and 206 can be constructed so that no inhibitor circuits are incorporated Need to become. In addition, the control signals do not have to be on two Y / s, i.e. only on one high and one low Potential level, are limited. For example, it is possible to use control signals which have any potential level have, for example, signals with a sinusoidal waveform.

" 'Display panel Figs. 24a and 24b show a part of an embodiment of an electrode arrangement in a liquid crystal." 60 dots and created by the electrodes 281, 60 dots and created by the electrodes 282, and 12 points, generated by electrodes 283 and 287 are used to display seconds, minutes and hours, respectively, electrodes 285, 286 and bind each divided into 12 parts and connected via conductor 288

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connected to a row control circuit. The electrodes 281 and 232 are divided into 5 parts and together with the electrode 283 connected via conductor 284 to the column control circuit. It can be seen that only 23 conductors can select any point on the hour, minute or second display enable. Since there is no voltage at the selected point, the indicating state is not brought about. The coloring is brought about at the unselected point. It is understood that there is a twist dependent nematic Liquid crystal is possible to bring about the displaying state of only the selected point when the orientation the polarizing plates is changed.

Fig. 25 shows an embodiment in which the inventive Display device is used in an electronic computer. In this case, the display device is used to display a graphical representation of the results of the calculations. At 291 is a liquid crystal display panel referred to, which is formed by the fact that nematic liquid crystals sandwiched between two glass plates are arranged, two polarizing plates and a reflective back plate are also provided. The graphic display part 292 is made of a liquid crystal material sandwiched between two sheets of glass is arranged, one of which is provided with longitudinally arranged transparent strip-shaped conductors 293, while the other transversely arranged conductor 294 of the same Type. The conductors 294 are with a first Control circuit connected and are supplied with independent control signals. The ladder 293 are on one Column control circuit and are either with signals that Are independent of any of those signals impressed or supplied with signals on conductors 294 only a signal is the same as a signal on conductors 294. It is thus possible to view an individual

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- yr-

Display element from a column of display elements in accordance with the type of lying on the conductors 293 To delete signals or to bring about the display state of the individual display element, so that a graphic Representation of any single-valued function can be displayed. It goes without saying that a two-valued function is indicated can be made by making use of every other longitudinal conductor 293, or that multivalent Functions can be easily represented by using a facility that alternates every other Second displays another graph. The coordinate axes and the coordinate divisions can be based on the Glass of the display panel can be printed, but it is also possible to make use of liquid crystals to create a Generate time-sharing ad or time-interleaved ad.

In the above-mentioned examples, therefore, control using a small number of control signals can itself take place when a display field with a plurality of display elements is provided. So it is enough just to use one type of control voltage while at the same time crosstalk and time delay due to excessive responsiveness are excluded and ensured that sufficient contrast is obtained.

Fig. 26 shows another example of a divided display element electrode pattern in the case where the Control should take place in the manner according to the invention. Information that indicates hours and minutes is provided via a 7-segment display element displayed. Figures 26a and 26b show how the row electrodes and the column electrodes Each are subdivided. 26c shows 7 segments, each of which is designated with a letter of the alphabet a to g is.

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In FIG. 26a, a line 311 is connected together with the electrodes a, d, e, f and g in FIG. 26c. This line 311 serves as a common electrode D1 for the 10 hour digit, the 1 hour digit, both minute digits and the second colon. The lead 312 is in common with the electrodes b and c in connection and serves as a common electrode D2 for the 1 hour digit and the two minute digits. In Fig. 26b, in which the division of the column electrodes is shown, the electrodes a, b and c, g are with each other connected j while the electrodes d, e and f with their neighbors are not connected and are therefore independent. In other words, the column electrodes only consist of 5 electrodes exist so that the number of electrodes is reduced by two.

Fig. 27 shows a symbolic representation of the electrodes subdivision of FIG. 26 and is provided with a name, which corresponds to the letters of the alphabet, which are called the electrodes in Fig. 26b. The electrodes Sab and Sgc are connected in a matrix form with respect to the electrodes D1 and D2. When electrodes are used, the manner illustrated 26 are divided as shown in Fig., Allow the electrodes connected in matrix to reduce the total number of display electrodes in comparison with a static control system. In other words, if a static control for displaying hours and minutes is performed, as shown in FIG. 26 , 23 column electrodes and one row electrode or a total of 24 electrodes are required. However, if the electrodes are divided as shown in FIG. 1, 17 column electrodes and 2 row electrodes will suffice, for a total of 19 electrodes. In addition, the electrodes a and d can be connected together when the display is used in a watch, since the 10 minute digit only counts to 5 before it goes back to 0. In this case the number of electrodes mentioned above can be further increased by one electrode be reduced. If, in addition,

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two 7-segment display elements added to enable a seconds display as well as an hour and minute display, the electrodes a and d of the 10 minute digit and the 10 second digit are interconnected, so that in contrast to 36 electrodes, which would be required for a static control system, only 27 electrodes are sufficient if the electrodes are divided in the manner shown in FIG. When adding 7-segment display elements to To display the month and date at the same time, there are only 43 electrodes as opposed to 58 electrodes in the static control system necessary. A division as shown in Fig. 26 thus shows that the number of necessary Electrodes is approximately 3/4 the number of electrodes required for a static control system.

In a static control system, when a signal applied to a common electrode is expressed as X, then are at the segment electrodes, two kinds of signals, namely the signal X for display and the signal X for non-display. If the for the work of a two digit matrix control system with two row electrodes created by dividing one common electrode can be obtained in two parts, signals lying on the digit electrodes are denoted by X and Y the signals on the column electrodes can be designated 01, 01, 02 and 02, which are completely independent of the signals X and Y and which are applied in accordance with whether the crossing points of the electrodes, that are connected to the matrix should be in the display or the non-display state.

In the control system according to the invention, when signals X and Y are applied to the row electrodes, the respective column electrodes are supplied with three types of signals, namely signals X and Y which are identical to the signals applied to the row electrodes, and a signal Z , that from

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the signals X and Y is independent. These signals are present depending on whether an indicating or non-indicating Condition is indicated.

Fig. 28 is used to describe the control signals that are used in the invention Display control system lie on the respective display elements. Fig. 28 (1) shows a frequency-divided signal 0 obtained from an oscillator and having a frequency of approximately 64 Hz. In Figs. 28 (2) and 28 (3) are Signals X and Y are shown, which are actually equal to the signal 0 divided by 2. The signal X is with the rising Edge of signal 0 and signal Y is synchronized with the falling edge of signal 0. In Fig. 28 (4) is a signal Z, which is equal to the signal X divided by 2. These three signals X, Y, Z are used to produce a liquid crystal display device with signal X on the D1 row of line 311 in FIG. 26 and signal Y on the D2 line of line 312 lie.

The signals X, Y and Z are optionally applied to the respective display elements depending on whether these elements are to display or not. It can be seen from Fig. 28 that the signals have two potential levels and that their voltages are determined by the optical saturation voltage Vg of the liquid crystal display elements. For example, if the optical saturation voltage V _g an effective value of 2 V is, 0 is satisfied, the signal a control function on a battery voltage of 1.5 V and the voltage at which the signals X, Y and Z carry out the control, twice the value of the signal 0 or 3 V.

Fig. 29 shows the application of the signals to the column electrodes as a function of whether they are to be placed in the displaying or non-displaying state when the electrodes in the manner shown in Fig 26 are divided.. In Fig.

29a, a circle symbol denotes a display element which is intended to display, while the symbol X denotes a display element is designated, which should not display. Those display elements which are only contained in the D1 line can be brought into the display state by applying the Y signal while the signal X is applied when the elements are not attached in an indicating state should. As far as the D1 line, the D2 line and the display elements switched in matrix form are concerned, this is still the case sufficient to apply the signal Z to both electrodes at the intersection points of the matrix, if the elements are to display. If an element should only display at a crossing point of the matrix and the other elements should not be displayed, the signal Y can be applied to the column for displaying its display elements and the signal X can be applied to the row to display its display elements.

Fig. 29b shows the signals applied to the respective column electrodes Sd, Se, Sf, Sab and Scg are placed on an electrode divided as shown in FIG. In this case, the numbers from 0 to 9 are displayed with the help of 7 segments, which are in accordance with those mentioned above Conditions of display or non-display can be controlled. For example, if you want to display the number 5, Fig. 9b indicates that the signal Y is applied to the electrode Sd and the signal X is applied to the electrode Se. From the drawing it can be seen that none of the crossing points of the electrodes connected in the matrix assume the non-indicating state will.

Fig. 30 shows the numbers from 0 to 9 formed by the 7 segments. That the electrodes are divided as shown in Fig. 26 is due to the fact that the segments connected in matrix ab and cg never both in

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are in a non-indicating state.

When signals having the waveforms shown in Fig. 28 are sent to the display electrodes of a liquid crystal display device are placed, the display elements are excited for display by an effective voltage of 1/2 V while on the display elements a voltage equal to 0 is applied to the non-display which are located at the crossing points of the matrix. In in this case, V is the voltage of signals X, Y and Z. For example, if a battery voltage of 1.5 V is used and the signals X, Y and Z have a voltage of 3 V or twice the voltage of the battery, the display elements at an RMS voltage of 2.1 V.

By dividing the electrodes in the manner described above and using the waveforms shown it is thus possible to completely switch off crosstalk and to reduce the number of display electrodes.

Fig. 31 shows a block diagram for an electronic watch, which has a liquid crystal display device which is operated according to the control method according to the invention. With 361 is an oscillator, with 362 is a frequency divider and with 363 are the hour, minute and second counters for measuring time. With 365 is a decoder, with 366 a driver, at 367 is a block for generating the control signals shown in Fig. 28; and at 368 is a liquid crystal display device designated.

Figure 32 shows the decoder and driver circuits for the clock. The counters for the hours, minutes, seconds and the like are denoted by 413. If the counter 413 consists of a divide by 10 counter, then it is possible to produce output signals ^{A, B, C and D with a weight of 2 °, 2 1} , 2 ^{2 and 2 ^.} The decoder 414 is a 7 segment decoder and

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has the same structure as a decoder used in a conventional static control system is used. A driver for a 7 segment output signal is denoted by 416, the generates 5 segment output signals in response to signals X, Y and Z. The decoder 415 directly decodes the counter output signals for 5 segments, and a 5 segment driver 417 operates to the signals X, Y and Z in a manner similar to that of the driver 416. Denoted at 418 is a liquid crystal display device. In this embodiment, information regarding the numbers from 0 to 9 is to be displayed so that five Column electrodes and two row electrodes are required. Which decoder is used depends on the data the clock. The structure of the decoder and driver circuits described below is based on electrodes that are used in the in 26 are divided.

33 shows the structure of the driver circuit 416. This example of a driver circuit is used for a display that shows seconds and minutes or something similar in the form of numbers from 0 to 9. The driver circuit combines the a, a, b, b ... g, g output signals, which are generated by a conventional 7-segment decoder, and the signals X, Y and Z and supplies the output signals for the columns Sab, Scg, Sd and Se and Sf. Lines 420, 421, 422 are the lines on which signals X, Y and Z are present, and line 423 supplies the g segment output signal from decoder 414. 424 is an AND gate and 425 is an OR gate. With regard to the Sf segment electrode, the following relationship is maintained: Sf = fY + fX. In other words, when the output signal f of the decoder is at a logic level H, the signal Y appears as the output signal, while when the output signal of the decoder is at the logic level L, the signal X is the output signal. The same is true for Sd and Se Seg ment electrodes to. Regarding the Sab segment electrode is

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Sab = abZ + HbX + abY. Thus, the signal Z appears as an off. output signal, if the a and the b segment are both at the logic level H, the signal X appears as an output signal, when the a segment is at the L level and the b segment is at the logic level H, and the signal appears Y as an input signal at the Sab electrode when the a segment is at the H level and the b segment is at the logic level L lie. The same is true for the electrode Scg.

It is thus understood that the driver circuit described above 416 makes use of a decoder that has the same Has construction like those decoders used in a conventional static control system.

Fig. 34 shows a second decoder and a second driver circuit according to the present invention. Block 391 gives the decoder part and block 392 gives the driver part again. Like the embodiment shown in FIG. 33, this embodiment is also suitable for numbers from O to 9, and in accordance with the structure in In Fig. 32, the decoder 415 is represented by the block 391 in Fig. 34, and the construction of the driver circuit 417 is shown block 392 in FIG. 34 is reproduced.

Lines 430 and 431 in Fig. 34 provide output signals from the counters represented by A, B, C and D. and having weights of 2 °, 2 ¹ , 2 ² and 2 ^3, respectively. 432 is an AND gate and 433 is an OR gate. In the following, an example is given in which an output signal from the decoder is applied to the input side of the electrode Se. From the table of values in FIG. 29b, X = AD + ABC + BCD and Y = A "BD" + ABC. In other words, when the output signals from the counter satisfy these relationships, signals X and Y are applied to the input side of the electrode Se. For the electrode Se, the output signal ABD "+ ABC = P.

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This output signal from the decoder is applied to the driver circuit represented by block 392. The logical function for the driver circuit is given by X χ »ρ + γ« ρ. The signal Y is present at the electrode Se when the output signal P of the decoder is at the logic level H , and the signal X when the output signal P is at the logic level L , the signal Y being an indicating state and the signal X being indicates non-indicative state .

The table of values according to Flg. 29b is used as in the previous case. The logical equations in this case are:

X ■ ABCD + ABCD Y = ABCD + ABCD JS β ABD + AOD + BCD

The right-hand sides of the above relationships are formed by the AND and OR gates of the decoder , and the driver circuit

392 decides, depending on whether the decoded signals indicate an indicating or non-indicating state , which of the signals X, Y and Z is to be applied to the inputs of the display electrode Sab.

The decoder and driver circuits shown in Figs are shown differ in their structure depending on the specification of the segment electrode arrangement with respect to the digit electrodes. The circuits can therefore be modified in many ways, and the above The circuits described in the present exemplary embodiment represent only one of the possibilities. In addition For example, the signals applied to the display electrodes are not limited to signals having the waveform shown in FIG to have.

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Fig. 35 shows a modified example of the display control signals. 35 (1), (2) and (3) show signals X, Y and Z. In this case, the same relationships exist as in the case of FIG Conditions of Fig. 29. When the control signals shown in this embodiment are used, on the elements that are to be brought into a displaying state are applied voltages with a waveform that is typical have the shape shown in Fig. 35 (4). The on the display elements in this case impressed effective voltage is Y2 / 3 of the battery voltage. If the battery voltage is thus If the value is 3 V, the rms voltage is 2.45 V. An element that is not supposed to display has a voltage of 0 V.

Fig. 36 shows another modified example of the waveforms that can be used for control. Figs. 36 (1), (2) and (3) show the signals X, Y and Z, respectively, all of which have the same frequency. When the illustrated phase relationship is used, an interval occurs over which a voltage of 0V is applied across the electrodes of the display elements to be displayed during part of the intermediate time in which the direction of the applied voltage is reversed. The amount of electricity charged in the capacitance between the electrodes at this time flows through a discharge path without passing through the power source, so that unnecessary power consumption can be avoided.

In this control system, the following relationships exist between the voltages of signals X, Y and Z. If the mean voltage of signals X, Y and Z with respect to time is given in the form of a reference voltage:

1) An interval occurs over which the voltage of the signals X, Y has the same sign.

2) Preferably this interval has a total value greater than 1/2, but less than 3/4 (2/3 is most preferred).

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3) During this interval signal Z has the same sign as signals X and Y, the remainder of the waveform is but different in sign.

4) The interval over which Z has the same sign as X and Y, and the interval over which Z has the same sign as the signals X and Y have different signs, each is preferably half of the interval specified under point 3).

5) An interval occurs over which the voltages of signals X and Y differ in sign.

6) During part of the interval specified under point 5) the signal Z has the same sign as the signal X, but differs in sign during the other Part of the interval.

7) The interval mentioned under point 6), over which the signals X and Z share the same sign, is preferably half of the respective intervals listed under point 6),

8) The rms voltages of (X-Y), (X- Z) and (Y - Z) are approximately the same.

9) The signals X, Y and Z can assume several voltage levels, although the circuit can be constructed more simply if only two voltage levels are used, as in the Drawing is shown.

37 is a diagram showing the waveform of row and column control signals applied to a display device, which is arranged in a matrix form using four row electrodes. In Fig. 37, R1 to R4 are the line control signals denotes which are located on the first to fourth row electrodes, respectively. Co denotes a column control signal, in order to bring the display elements on all row electrodes into the non-display state. With C12, C13, C14, C23, C24 and C34 are designated column control signals, the display elements on two row electrodes in one are not bring the display state. Designate C123, C134, C234 Column control signals that a display element on one of the line

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Bring the electrodes into a non-indicating state. C1234 denotes a column control signal which brings display elements on all row electrodes into the displaying state. The index 1,2,3,4 at the letter C indicates the number of the row electrodes whose display elements are to show. A cycle duration T contains an addressing time from the time intervals Tal, Ta2, Ta3. And Ta4 and a non-addressing time from a time interval Tn. During the addressing time, the row control signals R1 to R4 have the voltage potential V1 during / time intervals Ta1 to Ta4, respectively. During the non-.dressing time, which corresponds to the time interval Tn, the voltage potentials of all row control signals are the same. It will be found that during the addressing time one of the row electrodes is at a potential level which is different from the potential level of the remaining row electrodes during each of the time intervals. During the time interval Ta1 is thus R2 = R3 = R4 £ R1, during the time interval TalT'ist R1 = R3 = R4, R2, during the time interval is Ta3. . R1 = R2 = R4 φ R3 and during the time interval Ta4, R1 = R2 = R3 £ R4.

In order to bring the display elements of all row electrodes into a non-display state, a voltage potential which is equal to the voltage potential of the three row electrodes, as represented by the column control signal Co, is applied to the column electrode. During the time interval Ta1, Co = R2 = R3 = R4, during the time interval Ta2, Co = R1 = R3 = R4, during the time interval Ta4, Co - R1 = R2 = R3, and during the time interval Tn, Co = R1 = R2 = R3 = R4.

In order to bring the display elements of two row electrodes into a non-display state, the row electrode is with a voltage potential equal to that applied to the non-displaying row electrodes during the time intervals during

ζ ·
to which they are addressed, with a voltage potential, that

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differs from the potential which is applied to the indicating row electrodes during the time intervals during which they are addressed and is supplied with the same voltage potential which is applied to all row electrodes during the non-addressing time interval. For example, the column control signal C12 has the voltage potential O equal to that of the row control signals RjJf R4 during the time intervals Ta1 and Ta2 during which the non-display row electrodes R3, R4 are addressed, ie C12 = R3 = R4. During the time intervals Ta1 and Ta2, during the displaying of row electrodes addressed R1 and R2, however, has the column control signal a voltage potential from that of the line control signals R1 and R2 is different, so that C12 f R1 and C12 fi R2. During the time interval Tn, C12 = R1 = R2 = R3 β R4. With these waveforms of the control signals applied to the row and column electrodes, the rms value of the control signal applied to the display element in the display state is - / 3 / ί? V and in the non-display state "VTTB V. In this case the working margin is ~ p. It will be understood that the basic concept of forming the line and column control signals can also be applied to the case where the display device is more than having five row electrodes, which are arranged in matrix form.

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-se -

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Claims (13)

2727Q10 claims 1. method of operating an electro-optical display device with row and column electrodes arranged in a matrix form so that display elements on the intersections between the row and column electrodes are provided in such a way that the number χ of the display elements along a column electrode in the not display state, the other display elements of which are brought into a display state, satisfies the following relationship: <· ■■
x = η - l where η is the total number of row electrodes, 1 is an integer greater than a value k, however is smaller than η,
k is expressed as: ' n ² + nl- / n ³ -n + l 2n where k is the largest integer that has the above relationship fulfilled, characterized in that two line control signals always have a voltage potential that satisfies the following relationship: where T = a cycle duration, ri = voltage potential of the i-th line control signal,
rj = voltage potential of the j-th row control 709852/0958
ORIGINAL INSPECTED signals,
t = time,
R = constant, and that the column control signals have voltage potentials which satisfy the following relationship: Eon /..'"■
C ν ro = A 211 (ri-ro) where C = voltage potential of a column control signal which brings η - 1 display elements into a non-display state and the other display elements into a display state, ro = mean voltage potential of all row control signals,
A = constant, = Sum of the row electrodes with display elements, which are brought into the indicating state, where A has at least one of the following relationships Fulfills: A - 2 / (n - I ) 2. The method according to claim 1, characterized in that there is a column control signal Cl is among the column control signals, which brings a display element on 1 lines in a display state and a display element on (n - 1) lines in a non-display state, and that in V _e ktordarstellung this row control signal Cl in a line is, the r all row control signals and the average value r the average value - - of the line control signals for the display elements on the row electrodes to be brought into Einei not to be displayed state, connect ^, and that Cl, r _Qif , r _{Q in} such a way 709852/0958 gen that the distance between Cl and r is twice as large as the distance r _Q and r -. 3. The method according to claim 1, characterized in that η = 3, and that in vector representation the line control signals are the vertices of an equilateral triangle occupy, which lie on a circle with the radius R and the center Co, which is the column control signal, which brings the display elements of all row electrodes into a non-display state. 4. The method according to claim 1, characterized in that η = 4, and that the line control signals in vector representation occupy the vertex of a regular tetrahedron and lie on a spherical surface, its center is the column control signal Co which turns the display elements on all of the row electrodes into a non-display State brings. 5. The method according to claim 1, characterized in that χ is less than 2. 6. The method according to claim 5, characterized in that the column control signals comprise a control signal which is identical in waveform to the row control signals, and a control signal which is different in waveform from the row control signals. 7. The method according to claim 6, characterized in that the row and column control signals are time-multiplied. 8. The method according to claim 1, characterized in that the electro-optical display device is a liquid crystal and has first and second row electrodes and first Column electrodes intersecting the first and second row electrodes and having two column electrodes, 709852/0958 which only cut either the first or the second row electrodes that at the first and second row electrodes first and second control signals are, and that on the second column electrodes either the first or the second control signals are in each case, while optionally the first column electrodes first and second control signals and a third control signal are dependent on whether an indicating or a non-display state is desired. 9. The method according to claim 6, characterized in that the level of the first, second and third control signals changes between two potential levels. 10. The method according to claim 8, characterized in that the first and second control signals have their waveform but are out of phase, and that the third control signal differs in waveform from the first and second control signals. 11. The method according to claim 8, characterized in that the first and second control signals have different waveforms, and that the third control signal has a waveform which is identical to the waveform of the second control signal, the second and the third Control signals are out of phase with each other. 12. The method according to claim 8, characterized in that the first, second and third control signals are the same Have frequency and 'are out of phase with one another. 13. The method according to claim 1, characterized in that the number i of row electrodes is greater than 3, that the column electrodes in matrix form with the i x row electrodes are arranged so that the row and column control signals change between two potential levels,. 709862/0958 -S- that the row control signals have a first voltage potential during prescribed time intervals Ta1 .... Tai within an addressing period of a cycle period and a second voltage level during a non-addressing period Tn in the cycle time, and that the column control signals have voltage potentials such that at the column electrodes a voltage potential equal to that of the row control signals during the prescribed Time intervals Ta1 ... Tai lies around the display elements of all row electrodes in a non-display To bring state that to the display elements of two row electrodes in the non-display state bring, at the column electrodes a voltage potential equal to that at the row electrodes for the non-indicating State potential during the time intervals over which these row electrodes are addressed are, a voltage potential that differs from that voltage potential that is at the row electrodes for the indicating state lies during the time intervals during which this row electrodes are addressed are, and a voltage potential is equal to that of all row electrodes during the non-addressing Time interval Tn, and that a column electrode, the display element, which is a row electrode cuts, is to be brought into a non-indicating state, is supplied with a voltage potential that is differs from that potential which is applied to the row electrodes during the time interval over which one of the row electrodes is addressed, and that a column electrode, its display elements, all of the row electrodes cut, are to be brought into the indicating state, with a voltage potential that differs from differs from that potential which is applied to the row electrodes during the addressing period, and is supplied with a voltage potential that is equal to 709852/0958 is that potential which is applied to the row electrodes during the non-addressing period of time. 709852/0958